.375 H&H mag, 2012 cartridge of the year?

2012 is almost upon us, I would like to get in early and stake a claim for the .375 H&H Mag as cartridge of the year. Possibly the most sucessful cartridge of the past 100 years ( it was introduced in 1912) with no history of military service and from an obscure orgin.
Apart from gaining worldwide acceptance i suggest it has ‘fathered’ more calibres than any others. just a quick scan gives me the following but there are others, including many wildcats,

.244 H&H Mag
.257 Weatherby
6.5mm Rem Mag
.264 Win Mag
.270 Weatherby Mag
.275 H&H
7mm Weatherby
7mm Rem Mag
.300 Win Mag
.300 H&H Mag
.308 Norma Mag
.300 Weatherby Mag
8mm Rem Mag
.338 Win Mag
.340 Weatherby Mag
.350 Rem Mag
.358 Norma Mag
.458 Win Mag

and there are others, I am looking for help to compile a definitive list, including wildcats and some help would be appreciated.

Great idea Vince.

It is short of amazing that after 100 years, the 375 is still made and sold by most of the major ammunition manufacturers around the world.

What many do not realize is that it is also a very accurate cartridge. Three-shot cloverleaf groups are not uncommon if the shooter can master the recoil. I’ll submit a list of the better wildcats that have crossed my path, including some of the loudenboomers used in Benchrest. And a photo or two also.


A quick trip thru my photo files turned up these wildcats based on the original 375 H&H belted case.

Four of the real loudenboomers of Benchrest. These are based on the full length belted case and are used primarily for 1000 yard group and score shooting.

In the 1950s and 1960s the 375 case was shortened to approximately 30-06 length in order to work through most bolt action rifles. These were referred to as the “Short Magnums”. (Not to be confused with today’s Short Magnums). Most of the wildcats made on the belted case are of this length. Here are four that are very similar in appearance, Shown with the 308 Norma magnum, one of the original Short magnums.

Finally, one of rarities, not often found in wildcat cartridge collections. The .228 Ackley Double Shoulder.

I think the .375 Weatherby Mag. was one of the first variations on this case?

I agree with Vince and Ray,
375 H&H is the father of a infinite list of cartridges, commercial, wildcats and military too

The 300 AMU was used as a sniper cartridge and the 458 1 1/2" Barnes, made cutting down a 458 Winchester magnum case saw someuse during the Vietnamese war

Your Ackley double shoulder cartridge must take the prize for the most unusual. What was the logic in deliberatly elongating the combustion space? virtually all the modern perceived wisdom suggests that as near spherical as you can get it works best.


Your Ackley double shoulder cartridge must take the prize for the most unusual. What was the logic in deliberately elongating the combustion space? virtually all the modern perceived wisdom suggests that as near spherical as you can get it works best.


IIRC (and going strictly from memory) it was an experiment to prove that a long skinny powder column was more accurate/efficient than a short fat column. IOW just the opposite of today’s “short & fat” fad.

Neither type of column has any measurable effect BTW. A gunsmith and a writer (C.Sisk and J.Barnes ?) noticed that the 300 H&H and the 300 WSM had the same capacity. They cut a H&H chamber, tested, than re-cut the chamber to the WSM leaving the leade & throat untouched and got the same velocities and groups with the same powder charges

I believe the rare .40 BSA is also derived from the .375 H&H.

I’d like to see the pressure diagram of the 228 Ackley DS. I would think that pressure peak would be smaller than that of a round with similar capacity and caliber, but with a standard case shape

I think we may be taking Ackley’s 228 Double Shoulder Magnum more seriously than he did. Ackley also had his playful side and there are other examples of cartridges of his design that were nothing more than “Hold my beer and watch this”! He did observe the efficiency, or lack thereof, when testing his odd ball cartridges, but even he would admit that most were impractical, at best. A true wildcatter.

Back to the 375 H&H based wildcats - Ackley’s books are the best source to compile a list of them. And, there are a LOT. Maybe more than cartridges based on the 30-06. And that is really saying something.


As an armchair enthusiast rather than any form of expert my take on it is this. The fire starts at the primer end. It then builds progressively through the charge in exactly the same way as it would if it was a fire in a wood pile ie from back to front.
By the time it reaches the front the fire in the back has already started to generate enough pressure to not only start moving the bullet forward but also to push the bulk of the burning powder and some unburnt or partially burnt powderin front of it up the barrel. This is not a desirable state of affairs.

This happens every time we pull the trigger on most standard rifle cartridges. Modern rifle powders love/need pressure to burn so the first stage results in a stalling effect on combustion lasting only a fraction of a thousanth of a second.

By now the air in the barrel is acting like a hydraulic damper impeding the forward movement of the bullet. Things catch up resulting in the “second burn” and another big push. Some ballistics experts suggest that the crisis point between the first burn and the second burn can actually result in the bullet stopping in the barrel. I don’t know if this is true but at about four to six inches into the barrel on most worn barrels there is a point of extra wear at this crisis point. Indicating that work ie considerable forces are at play

It goes to show that the combustion / pressure curve is actually a very complex subject. Much more than we give credit for.

I was also thinking about the Venturi paradox. When a flux of fluid ( so also the gases generated by a cartridge) is forced into a smaller diameter pressure goes down and there’s a gain in velocity.

There are some “stretched .458 Win” rounds in my collection: the .450 Watts, .450 Ackley, .458 Lott and .470 Capstick, the last three of which were all made by A-Square (or at least, the cases were). I also have a .425 Express, 416 HMFN, .416 Taylor, .358 STA (all by A-Square), the .416 Rem of course, and the .350 Griffin & Howe Magnum by Western.

I think that’s all my biggies…

Edit to add: .33 BSA

Some smaller calibre ones in my collection:
7mm STW, 7x61 Sharpe & Hart, .26 BSA, .264 PMS, .264 Salizbury, .257 Condor.

Here are some of the military/police purposed loads.

From left to right:

.22/.300 US Navy Xpl Match (no headstamp)
7mm Sniper (x63mm) (FCOTB 80)
.7.62 x 72B South African ballistic test (norma 300 WBY MAG)
.300 AMU (R-P 300)
.300 AMU (W C C 6 0)
.300 H&H (REM-UMC 300 MAGNUM)
.300 H&H (WESTERN .300 H&H MAGNUM)
.458 SSS (x33mm) (458 WINCHESTER MAGNUM)
.458 (x33mm) South African ballistic test, rim removed (458 WINCHESTER MAGNUM)